11AM JEANNE DISCUSSION

[charleston_hugo_veteran]

Tropical Storm Jeanne Discussion Number 24


Statement as of 11:00 am EDT on September 19, 2004



high resolution visible satellite images definitely show that the
low-level circulation has become large and better organized. There
are cyclonically-curved convective bands wrapping around the
system and the outflow is well-established. However...Jeanne lacks
an inner core which is normally associated with a stronger cyclone.
Therefore the initial intensity is kept at 40 knots. A
reconnaissance plane will check Jeanne later today. Given the
current conditions of low shear and the large circulation...some
strengthening is indicated. However...global models suggest that
very hostile westerly winds should begin to approach Jeanne in a
couple of days. Therefore...the intensity is increased only to 65
knots in the forecast which may be generous.

The large circulation appears to be moving northward at about 4
knots around the subtropical high and ahead of a mid-level trough.
There is confidence that this general motion will likely continue
during the next day or two. However...in about 3 days the steering
currents will weaken and Jeanne is forecast to meander between
Bermuda and the Bahamas for the rest of the forecast period. In the
long range...the forecast is highly uncertain. For example...recent
runs of the GFS have been alternating between an eastward and a
westward track...and solutions from the other global models have
not been any more conclusive. The latest five day forecast points
of the UKMET and GFS models are about 1200 N mi apart. In such
cases...the best option is to keep the cyclone meandering in
between the two equally valid model options.

Forecaster Avila

forecast positions and Max winds

initial 19/1500z 23.5n 72.5w 40 kt
12hr VT 20/0000z 24.8n 72.5w 45 kt
24hr VT 20/1200z 26.5n 71.5w 50 kt
36hr VT 21/0000z 27.5n 70.5w 55 kt
48hr VT 21/1200z 27.5n 70.0w 60 kt
72hr VT 22/1200z 26.5n 70.0w 65 kt
96hr VT 23/1200z 26.0n 70.5w 65 kt
120hr VT 24/1200z 26.0n 71.5w 65 kt